It's possible to create your iPhone app entirely in Swift Playgrounds, but you can also export projects into Xcode (Apple’s full-fat development environment).

It has sections that guide someone looking to begin making apps from starting, through set-up, tutorials, fundamentals, developing and guiding them to further resources.

Ultimately, developing for iOS could mean investing in a Mac, learning Xcode and Swift, investing hours and $$$ into development… only to have your app rejected.